This article in the journal Nutrition was pretty simple. A 19 year old male sought treatment for lack of libido and sexual dysfunction. He had voluntarily started a vegan diet previously. The study measured the effects of ceasing a vegan diet and removing soy from the diet.
Yeah, this study has been around for a couple months. Apparently I was a sleep at the wheel that day. I think Keith Norris posted it on facebook yesterday. Thanks!
Previous research has focused on the beneficial effects of soy and its active ingredients, isoflavones. For instance, soy consumption has been associated with lower cardiovascular and breast cancer risks. However, the number of reports demonstrating adverse effects of isoflavones due to their estrogenlike properties has increased. We present the case of a 19-y-old type 1 diabetic but otherwise healthy man with sudden onset of loss of libido and erectile dysfunction after the ingestion of large quantities of soy-based products in a vegan-style diet. Blood levels of free and total testosterone and dehydroepiandrosterone (DHEA) were taken at the initial presentation for examination and continuously monitored up to 2 y after discontinuation of the vegan diet. Blood concentrations of free and total testosterone were initially decreased, whereas DHEA was increased. These parameters normalized within 1 y after cessation of the vegan diet. Normalization of testosterone and DHEA levels was paralleled by a constant improvement of symptoms; full sexual function was regained 1 y after cessation of the vegan diet. This case indicates that soy product consumption is related to hypogonadism and erectile dysfunction. To the best of our knowledge, this is the first report of a combination of decreased free testosterone and increased DHEA blood concentrations after consuming a soy-rich diet. Hence, this case emphasizes the impact of isoflavones in the regulation of sex hormones and associated physical alterations.
Here are the results:
The left of the chart shows the subject’s testosterone levels upon initial testing, before cessation of vegan diet. The negative effects of the vegan/soy diet show a measured decrease after two weeks, but continued to improve for (at least) 724 days after quitting the vegan/soy diet.
The authors talk about proposed mechanisms (the wonderfully exciting world of isoflavones), et cetera, but I’ll leave it to someone else to bore you with those details.
Disclaimer bla bla bla
Obviously, a single individual can’t be assumed to represent the entire population.
- And before we get into some lame cavemen died at 30 argument, a friendly reminder: “Modal ages of adult death… under traditional conditions seems to be just after age 70 years” –Source
- There are older studies that say that soy has some benefits, but as the abstract says, “the number of reports demonstrating adverse effects of isoflavones due to their estrogenlike properties has increased.” The reasons for this are discussed specifically in the full-text of the article.
Not an isolated instance
Most veg*ns change to their way of eating for ethical reasons, most quit a veg*n diet because of health reasons. And contrary to what agrarian imperialists and feudal lords have been saying for a few thousand years, most of the ethical reasons are bogus as well.
Do your body and your planet a favor by avoiding soy. Seriously. Well, I mean… unless this is your goal… (Hey, I’m not judging)
Update: Mellisa McEwen wrote a post about this study that’s worth checking out.